Modern surgical procedures increasingly involve the cutting of bone material. For example, joint replacement surgery such as hip replacement involves the hollowing out of the interior of the femur to provide a cavity to accommodate an artificial implant.
It is known in the art that the heating of the bone during the cutting process should be minimized to avoid medical complications such as bone necrosis. Preferably, the temperature at the bone interface should not exceed about 50.degree. C. for more than 1 second. This is accomplished by minimizing heat generation during the bone cutting process and by maximizing heat removal from the cutting area. Heat is generally removed from the cutting area by a cutting fluid (e.g. saline solution) which functions as a heat sink and also removes bone chips from the cutting area.
U.S. Pat. No. 5,190,548 discloses a surgical bone reamer having a central bore in the shank of the reamer for carrying cutting fluid. The fluid exits the bore at the cutting head of the reamer and flows along the annular passageway between the shank and the bore hole. Unfortunately, at high speeds (e.g. greater than 40,000 to 50,000 rpm) centrifugal force will prevent the flow of cutting fluid through the central bore of the drill, thereby inhibiting cooling of the bone surface during the drilling process.
It is an object of the present invention to provide a high speed rotary bone cutter which reduces heat generation at the cutting surface and enhances heat removal from the cutting area. Other objects and advantages will be apparent from the following disclosure.